rust: Use aligned_as macro in voxel

Use updated macro by ExpHP from
https://users.rust-lang.org/t/can-i-conveniently-compile-bytes-into-a-rust-program-with-a-specific-alignment/24049/2

rust/voxel/src/aligned_as.rs

@@ -0,0 +1,24 @@
+/*! Align an array of bytes to a specified alignment. This struct is generic in Bytes to admit unsizing coercions.
+ * See: https://users.rust-lang.org/t/can-i-conveniently-compile-bytes-into-a-rust-program-with-a-specific-alignment/24049
+ */
+#[repr(C)] // guarantee 'bytes' comes after '_align'
+pub struct AlignedAs<Align, Bytes: ?Sized> {
+    pub _align: [Align; 0],
+    pub bytes: Bytes,
+}
+
+macro_rules! include_bytes_align_as {
+    ($align_ty:ty, $path:literal) => {
+        {  // const block expression to encapsulate the static
+            use $crate::aligned_as::AlignedAs;
+
+            // this assignment is made possible by CoerceUnsized
+            static ALIGNED: &AlignedAs::<$align_ty, [u8]> = &AlignedAs {
+                _align: [],
+                bytes: *include_bytes!($path),
+            };
+
+            &ALIGNED.bytes
+        }
+    };
+}

rust/voxel/src/main.rs

@@ -21,6 +21,8 @@ use k210_shared::soc::spi::SPIExt;
 use k210_shared::soc::sysctl;
 use riscv_rt::entry;
 
+#[macro_use]
+mod aligned_as;
 mod map_data;
 
 /** Euclidian modulus. */

rust/voxel/src/map_data.rs

@@ -1,18 +1,3 @@
-/** Align an array of bytes to a specified alignment. This struct is generic in Bytes to admit unsizing coercions.
- * See: https://users.rust-lang.org/t/can-i-conveniently-compile-bytes-into-a-rust-program-with-a-specific-alignment/24049
- */
-#[repr(C)] // guarantee 'bytes' comes after '_align'
-struct AlignedTo<Align, Bytes: ?Sized> {
-    _align: [Align; 0],
-    bytes: Bytes,
-}
-
-/** Dummy static used to create aligned data. */
-static ALIGNED: &'static AlignedTo<u16, [u8]> = &AlignedTo {
-    _align: [],
-    bytes: *include_bytes!("../data/map15.dat"),
-};
-
 pub static WIDTH: u32 = 256;
 pub static HEIGHT: u32 = 256;
-pub static VOXEL_MAP: &'static [u8] = &ALIGNED.bytes;
+pub static VOXEL_MAP: &'static [u8] = include_bytes_align_as!(u16, "../data/map15.dat");