foundation: primitive llinked list

crates/foundation/src/collections/linked_list.rs

@@ -0,0 +1,70 @@
+use core::ptr::NonNull;
+
+pub unsafe trait LinkedListNode {
+    fn next(this: NonNull<Self>) -> Option<NonNull<Self>>;
+    fn set_next(this: NonNull<Self>, next: Option<NonNull<Self>>);
+}
+
+pub struct LinkedList<T: LinkedListNode> {
+    head: Option<NonNull<T>>,
+}
+
+impl<T: LinkedListNode> LinkedList<T> {
+    pub const fn new() -> Self {
+        Self { head: None }
+    }
+
+    pub fn push_front(&mut self, node: NonNull<T>) {
+        T::set_next(node, self.head);
+        self.head = Some(node);
+    }
+
+    pub fn pop_front(&mut self) -> Option<NonNull<T>> {
+        let node = self.head?;
+        self.head = T::next(node);
+        Some(node)
+    }
+
+    pub fn remove_if(&mut self, mut predicate: impl FnMut(NonNull<T>) -> bool) {
+        let mut current = self.head;
+        let mut prev: Option<NonNull<T>> = None;
+
+        while let Some(node) = current {
+            if predicate(node) {
+                let next = T::next(node);
+                if let Some(prev_node) = prev {
+                    T::set_next(prev_node, next);
+                } else {
+                    self.head = next;
+                }
+                current = next;
+            } else {
+                prev = current;
+                current = T::next(node);
+            }
+        }
+    }
+
+    pub fn iter(&self) -> LinkedListIter<T> {
+        LinkedListIter { current: self.head }
+    }
+}
+
+impl<T: LinkedListNode> Default for LinkedList<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+pub struct LinkedListIter<T: LinkedListNode> {
+    current: Option<NonNull<T>>,
+}
+impl<T: LinkedListNode> Iterator for LinkedListIter<T> {
+    type Item = NonNull<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let node = self.current?;
+        self.current = T::next(node);
+        Some(node)
+    }
+}

crates/foundation/src/collections/mod.rs

@@ -0,0 +1 @@
+pub mod linked_list;

crates/foundation/src/lib.rs

@@ -15,6 +15,7 @@ extern crate alloc as liballoc;
 extern crate std;
 
 pub mod alloc;
+pub mod collections;
 pub mod sync;
 pub mod mem {
     use num_traits::PrimInt;