utils: move damage algorithms to algorithm crate

algorithms/src/windows.rs

@@ -0,0 +1,35 @@
+pub trait WindowsExt<T> {
+    type Windows<'a, const N: usize>: Iterator<Item = &'a [T; N]>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn array_windows_ext<'a, const N: usize>(&'a self) -> Self::Windows<'a, N>;
+}
+
+impl<T> WindowsExt<T> for [T] {
+    type Windows<'a, const N: usize> = WindowsIter<'a, T, N> where T: 'a;
+
+    fn array_windows_ext<'a, const N: usize>(&'a self) -> Self::Windows<'a, N> {
+        WindowsIter { slice: self }
+    }
+}
+
+pub struct WindowsIter<'a, T, const N: usize> {
+    slice: &'a [T],
+}
+
+impl<'a, T, const N: usize> Iterator for WindowsIter<'a, T, N> {
+    type Item = &'a [T; N];
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.slice.len() < N {
+            return None;
+        }
+        let res = unsafe { &*self.slice.as_ptr().cast::<[T; N]>() };
+        if N > 0 {
+            self.slice = &self.slice[1..];
+        }
+        Some(res)
+    }
+}