Add internal_queue

src/internal_queue.rs

@@ -1 +1,42 @@
+struct SimpleQueue<T> {
+    payload: Vec<T>,
+    pos: usize,
+}
 
+impl<T> SimpleQueue<T>
+where
+    T: Copy,
+{
+    fn reserve(&mut self, n: i32) {
+        let n = n as usize;
+        if n > self.payload.len() {
+            self.payload.reserve(n - self.payload.len());
+        }
+    }
+
+    fn size(&self) -> i32 {
+        (self.payload.len() - self.pos) as i32
+    }
+
+    fn empty(&self) -> bool {
+        self.pos == self.payload.len()
+    }
+
+    fn push(&mut self, t: &T) {
+        self.payload.push(*t);
+    }
+
+    // Do we need mutable version?
+    fn front(&self) -> &T {
+        &self.payload[self.pos]
+    }
+
+    fn clear(&mut self) {
+        self.payload.clear();
+        self.pos = 0;
+    }
+
+    fn pop(&mut self) {
+        self.pos += 1;
+    }
+}