transpose out of place for rot_90 cloner

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fimg"
-version = "0.4.12"
+version = "0.4.13"
 authors = ["bend-n <bend.n@outlook.com>"]
 license = "MIT"
 edition = "2021"
@@ -9,6 +9,7 @@ repository = "https://github.com/bend-n/fimg"
 exclude = ["tdata", "benches/", ".gitignore"]
 
 [dependencies]
+mattr = "0.0.2"
 png = { version = "0.17", features = ["unstable"], optional = true }
 
 [dev-dependencies]

benches/affine_transformations.rs

@@ -1,7 +1,7 @@
 use fimg::*;
 
 macro_rules! bench {
-    (fn $name: ident() { run $fn: ident() }) => {
+    (fn $name: ident() { run $fn: ident() } $($namec:ident)?) => {
         fn $name() {
             let mut img: Image<_, 4> =
                 Image::build(128, 128).buf(include_bytes!("4_128x128.imgbuf").to_vec());
@@ -12,12 +12,24 @@ macro_rules! bench {
                 };
             }
         }
+
+        $(fn $namec() {
+            let img: Image<&[u8], 4> =
+                Image::build(128, 128).buf(include_bytes!("4_128x128.imgbuf"));
+            #[allow(unused_unsafe)]
+            unsafe {
+                std::hint::black_box(img.cloner().$fn())
+            };
+        })?
     };
 }
 
-bench!(fn flip_h() { run flip_h() });
+bench!(fn flip_h() { run flip_h() } flip_hc);
-bench!(fn flip_v() { run flip_v() });
+bench!(fn flip_v() { run flip_v() } flip_vc);
-bench!(fn rotate_90() { run rot_90() });
+bench!(fn rotate_90() { run rot_90() } rot_90c);
-bench!(fn rotate_180() { run rot_180() });
+bench!(fn rotate_180() { run rot_180() } rot_180c);
-bench!(fn rotate_270() { run rot_270() });
+bench!(fn rotate_270() { run rot_270() } rot_280c);
-iai::main!(flip_h, flip_v, rotate_90, rotate_180, rotate_270);
+iai::main!(
+    flip_h, flip_v, rotate_90, rotate_180, rotate_270, flip_hc, flip_vc, rot_90c, rot_180c,
+    rot_280c
+);

src/affine.rs

@@ -107,9 +107,18 @@ impl<const CHANNELS: usize> ImageCloner<'_, CHANNELS> {
     /// UB if the image is not square
     #[must_use = "function does not modify the original image"]
     pub unsafe fn rot_90(&self) -> Image<Vec<u8>, CHANNELS> {
-        let mut out = self.flip_v();
+        let mut out = self.alloc();
+        // SAFETY: yep
+        unsafe {
+            mattr::transpose(
+                self.flatten(),
+                out.flatten_mut(),
+                self.height() as usize,
+                self.width() as usize,
+            )
+        };
         // SAFETY: sqar
-        unsafe { transpose(&mut out.as_mut()) };
+        unsafe { crev(out.as_mut()) };
         out
     }
 
@@ -157,6 +166,26 @@ impl<const CHANNELS: usize, T: DerefMut<Target = [u8]>> Image<T, CHANNELS> {
     }
 }
 
+/// Reverse columns of square image
+/// # Safety
+///
+/// UB if supplied image not square
+unsafe fn crev<const CHANNELS: usize, T: DerefMut<Target = [u8]>>(mut img: Image<T, CHANNELS>) {
+    debug_assert_eq!(img.width(), img.height());
+    let size = img.width() as usize;
+    let b = img.flatten_mut();
+    for i in 0..size {
+        let mut start = 0;
+        let mut end = size - 1;
+        while start < end {
+        	// SAFETY: hmm
+            unsafe { b.swap_unchecked(i * size + start, i * size + end) };
+            start += 1;
+            end -= 1;
+        }
+    }
+}
+
 /// Transpose a square image
 /// # Safety
 ///

src/lib.rs

@@ -10,8 +10,7 @@
     portable_simd,
     array_windows,
     const_option,
-    array_chunks,
+    array_chunks
-    test
 )]
 #![warn(
     clippy::missing_docs_in_private_items,
@@ -300,7 +299,7 @@ impl<T: std::ops::Deref<Target = [u8]>, const CHANNELS: usize> Image<T, CHANNELS
 
     #[inline]
     /// Flatten the chunks of this image into a slice of slices.
-    pub fn flatten(&mut self) -> &[[u8; CHANNELS]] {
+    pub fn flatten(&self) -> &[[u8; CHANNELS]] {
         // SAFETY: buffer cannot have half pixels
         unsafe { self.buffer.as_chunks_unchecked::<CHANNELS>() }
     }