initial mask impl

src/util/id.rs

@@ -1,25 +1,81 @@
-#[derive(Eq, Hash, PartialEq, Debug, Clone, Copy)]
-pub struct Id(u64);
+#[repr(C)]
+#[derive(Eq, Hash, PartialEq, Debug, Clone, Copy, bytemuck::Zeroable)]
+pub struct Id<I = u64>(I);
 
-#[derive(Default)]
-pub struct IdTracker {
-    free: Vec<Id>,
-    cur: u64,
+unsafe impl<I: Copy + bytemuck::Zeroable + 'static> bytemuck::Pod for Id<I> {}
+
+pub struct IdTracker<I = u64> {
+    free: Vec<Id<I>>,
+    cur: Id<I>,
 }
 
-impl IdTracker {
+impl<I: IdNum> IdTracker<I> {
     #[allow(clippy::should_implement_trait)]
-    pub fn next(&mut self) -> Id {
+    pub fn next(&mut self) -> Id<I> {
         if let Some(id) = self.free.pop() {
             return id;
         }
-        let id = Id(self.cur);
-        self.cur += 1;
-        id
+        let next = self.cur.next();
+        std::mem::replace(&mut self.cur, next)
     }
 
     #[allow(dead_code)]
-    pub fn free(&mut self, id: Id) {
+    pub fn free(&mut self, id: Id<I>) {
         self.free.push(id);
     }
 }
+
+impl<I: IdNum> Id<I> {
+    pub fn idx(&self) -> usize {
+        self.0.idx()
+    }
+    pub fn next(&self) -> Id<I> {
+        Self(self.0.next())
+    }
+    pub const fn preset(value: I) -> Self {
+        Self(value)
+    }
+}
+
+impl<I: IdNum> Default for IdTracker<I> {
+    fn default() -> Self {
+        Self {
+            free: Vec::new(),
+            cur: Id(I::first()),
+        }
+    }
+}
+
+pub trait IdNum {
+    fn first() -> Self;
+    fn next(&self) -> Self;
+    fn idx(&self) -> usize;
+}
+
+impl IdNum for u64 {
+    fn first() -> Self {
+        0
+    }
+
+    fn next(&self) -> Self {
+        self + 1
+    }
+
+    fn idx(&self) -> usize {
+        *self as usize
+    }
+}
+
+impl IdNum for u32 {
+    fn first() -> Self {
+        0
+    }
+
+    fn next(&self) -> Self {
+        self + 1
+    }
+
+    fn idx(&self) -> usize {
+        *self as usize
+    }
+}