fix debug_assert and add test for repeat

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fimg"
-version = "0.3.3"
+version = "0.3.4"
 authors = ["bend-n <bend.n@outlook.com>"]
 license = "MIT"
 edition = "2021"

src/lib.rs

@@ -372,3 +372,13 @@ macro_rules! img {
 }
 #[cfg(test)]
 use img;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn repeat() {
+        let x: Image<&[u8], 3> = Image::build(8, 8).buf(include_bytes!("../benches/3_8x8.imgbuf"));
+        unsafe { x.repeated(128, 128) }; // repeat 16 times
+    }
+}

src/overlay.rs

@@ -131,8 +131,9 @@ impl OverlayAt<Image<&[u8], 3>> for Image<&mut [u8], 3> {
                     let o_x = ((j + y as usize) * self.width() as usize + x as usize) * 3
                         ..((j + y as usize) * self.width() as usize + x as usize + ($n as usize))
                             * 3;
-                    debug_assert!(o_x.end < self.buffer().len());
-                    debug_assert!(i_x.end < with.buffer().len());
+                    // <= because ".." range
+                    debug_assert!(o_x.end <= self.buffer().len());
+                    debug_assert!(i_x.end <= with.buffer().len());
                     // SAFETY: bounds are ✅
                     let a = unsafe { self.buffer.get_unchecked_mut(o_x) };
                     // SAFETY: we are in ⬜!